Gulf Coast Empidonax Flycatcher Identification

What started out as a pretty routine exercise in shooting (photos) first and identifying later quickly turned into a mess when I tried to identify this flycatcher I photographed yesterday in Louisiana’s Atchafalya Basin. So, I thought I’d do a quick write up on what I’ve learned today in hopes of summarizing and maybe helping to understand this difficult to identify group of birds.

Empidonax on the Gulf Coast:

Empidonax is a genus of birds belonging to the family Tyrannidae (Tyrant Flycatchers) of whose North American ranks also includes kingbirds, phoebes, pewees, the great kiskadee and Myiarchus flycatchers. Empidonax (aka “empid”) Flycatchers are small insectivorous birds with generally olive/gray backs, lighter underparts, wing bars and eye rings. This group of birds is notoriously hard to identify.

According to George Lowery’s “Louisiana Birds” there are four (five now) empidonax flycatchers that may be commonly found in Louisiana. Acadian Flycatchers are a very common summer species in the Gulf South and the only empidonax that breeds in our area. Alder, Least, Willow and Yellow-bellied Flycatchers may be found during migration. Until the 1970’s, Alder and Willow flycatchers were considered to be the same species; Traill’s Flycatcher.

Many guides I’ve found and people I’ve talked to present such a hodge-podge of random information that it almost seems to border on the superstitious. However, one thing everyone seems to agree on is that the best way to identify an empidonax flycatcher is by song. Unfortunately for me, this has taken my usual method for learning identification by taking photos in the field followed by hours of study in front of the computer, completely upside down.

So, if you’re only working from pictures until you learn some bird calls, here are a few visual and behavioral clues that can help narrow down what species you’re looking at. However: One note of caution is that depending on the stage of molt, variation can be such that no one feature can give a positive ID.

Acadian: Our most common and only breeding empidonax flycatcher. Nests 10-15′ off the ground usually in swamps. Upperparts can be as olive green as a Yellow-bellied or as dull as an Alder/Willow depending on the stage of molt. Has a white throat with good contrast between the white of the throat and the gray of the face. Usually has a narrow, incomplete white/yellow eye ring.

Alder & Willow: Nearly identical. Generally only identified by song. Upperparts more brownish gray on Willow and very slightly olive gray on Alder. Willow has little to no eye ring while Alder has a distinct but very narrow eye ring.

Least: Smallest of the group. Olive gray upperparts, very distinct eye ring and small bill.

Yellow-bellied: Bold, complete eye ring, olive malar blends into throat with very little contrast. Some guides say that this species is the easiest empidonax to identify as no other empidonax has yellow under parts all the way up to the throat (though Lowery disagrees).

There are also differences in primary feather projection, bills and tail ratios that can be used to identify the species. For further reading on the math of empids, check out the Reference section at the bottom of this page.

Conclusion?

So, in conclusion… uh…. well. The bird from the top of the post is definitely an empidonax. I originally believed it may be a Yellow-bellied Flycatcher because:

Early September is a reasonable time that this species may be moving through this area

I did some asking around on the Louisiana birding community and the general consensus was that it was either a Yellow-bellied or an Acadian but without a frontal photo to see if the yellow runs all the way up to the throat, it’s not going to be a sure thing.

EDIT: Based on continuing conversations with some experts, I’m going to go with Yellow-bellied Flycatcher. I’ll make sure to post a picture and list diagnostics on eBird when I log it.

Thanks for reading! Enjoy some photos of empidonax flycatchers I’ve taken this year.

Honey Island Swamp; Pearl River, Louisiana – June 2014Most likely an Acadian based on time/geography, sharp face-throat contrast.Grand Isle, Louisiana – May 3, 2014
I identified this bird as Acadian by its vocalization. You can also see sharp contrast between the face and throat. Also notice how gray this bird is. The variation can be pretty significant.

Muir Woods, California – July 11, 2014Not a Gulf Coast flycatcher! I visited Muir Woods National Park this summer when I was in San Francisco for a friend’s wedding and saw several Pacific-slope Flycatchers. I identified this species mainly be range and geography and that nicely pointed eye ring.